Field of the Invention
The present disclosure relates to a radiation tube applicable to non-destructive X-ray inspection apparatuses in an industrial equipment field or a medical equipment field and a radiation inspection apparatus using the radiation tube.
Description of the Related Art
Radiation tubes produce radiation, such as an X-ray, by applying a high voltage between a cathode and an anode and emitting electrons from an electron source to a target. For example, a radiation tube is applied to an inspection apparatus for inspecting a foreign substance in an article as an X-ray source.
Japanese Patent Laid-Open No. 2013-88199 describes an X-ray inspection apparatus including an X-ray source that emits an X-ray beam to an article, a slit forming member that controls the irradiation area of the X-ray beam, and a conveyance unit that conveys an article.
FIG. 10 illustrates an existing X-ray inspection apparatus 301. The X-ray inspection apparatus 301 conveys an article to be inspected 307 using a conveyance unit 304, emits an X-ray beam from an X-ray tube 302 to the article 307, and detects the X-ray beam passing through the article 307 using an X-ray line sensor 305. The X-ray inspection apparatus 301 controls the irradiation area of an X-ray beam 308 in the shape of a cone emitted from an X-ray tube 302 using a slit forming member 306 having a slit extending in a direction perpendicular to a direction in which the article 307 is conveyed. The dashed arrows indicate X-ray beams scattered from the slit forming member 306. To block the X-ray beams from being emitted to the outside of an inspection space, an X-ray shielding wall 309 is provided.
In the X-ray inspection apparatus 301, a distance between an X-ray focal position (a target) and the slit is large and, thus, the X-ray is scattered into a wide area between the target and the slit. Accordingly, an area in which the X-ray shielding wall 309 needs to be provided increases. As a result, the size of the apparatus is disadvantageously increased.